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[SOFT386]

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Implement short conditional jump opcodes.


svn path=/branches/ntvdm/; revision=59856
This commit is contained in:
Aleksandar Andrejevic 2013-08-28 17:52:21 +00:00
parent 3ad78aac17
commit 1143eab8a5
2 changed files with 116 additions and 16 deletions
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124
lib/soft386/opcodes.c
View file

@ -136,22 +136,22 @@ Soft386OpcodeHandlers[SOFT386_NUM_OPCODE_HANDLERS] =
NULL, // TODO: OPCODE 0x6D NOT SUPPORTED
NULL, // TODO: OPCODE 0x6E NOT SUPPORTED
NULL, // TODO: OPCODE 0x6F NOT SUPPORTED
NULL, // TODO: OPCODE 0x70 NOT SUPPORTED
NULL, // TODO: OPCODE 0x71 NOT SUPPORTED
NULL, // TODO: OPCODE 0x72 NOT SUPPORTED
NULL, // TODO: OPCODE 0x73 NOT SUPPORTED
NULL, // TODO: OPCODE 0x74 NOT SUPPORTED
NULL, // TODO: OPCODE 0x75 NOT SUPPORTED
NULL, // TODO: OPCODE 0x76 NOT SUPPORTED
NULL, // TODO: OPCODE 0x77 NOT SUPPORTED
NULL, // TODO: OPCODE 0x78 NOT SUPPORTED
NULL, // TODO: OPCODE 0x79 NOT SUPPORTED
NULL, // TODO: OPCODE 0x7A NOT SUPPORTED
NULL, // TODO: OPCODE 0x7B NOT SUPPORTED
NULL, // TODO: OPCODE 0x7C NOT SUPPORTED
NULL, // TODO: OPCODE 0x7D NOT SUPPORTED
NULL, // TODO: OPCODE 0x7E NOT SUPPORTED
NULL, // TODO: OPCODE 0x7F NOT SUPPORTED
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
Soft386OpcodeShortConditionalJmp,
NULL, // TODO: OPCODE 0x80 NOT SUPPORTED
NULL, // TODO: OPCODE 0x81 NOT SUPPORTED
NULL, // TODO: OPCODE 0x82 NOT SUPPORTED
@ -648,3 +648,95 @@ Soft386OpcodeExchangeEax(PSOFT386_STATE State, UCHAR Opcode)
return TRUE;
}
BOOLEAN
FASTCALL
Soft386OpcodeShortConditionalJmp(PSOFT386_STATE State, UCHAR Opcode)
{
BOOLEAN Jump = FALSE;
CHAR Offset = 0;
/* Make sure this is the right instruction */
ASSERT((Opcode & 0xF0) == 0x70);
/* Fetch the offset */
if (!Soft386FetchByte(State, (PUCHAR)&Offset))
{
/* An exception occurred */
return FALSE;
}
switch ((Opcode & 0x0F) >> 1)
{
/* JO / JNO */
case 0:
{
Jump = State->Flags.Of;
break;
}
/* JC / JNC */
case 1:
{
Jump = State->Flags.Cf;
break;
}
/* JZ / JNZ */
case 2:
{
Jump = State->Flags.Zf;
break;
}
/* JBE / JNBE */
case 3:
{
Jump = State->Flags.Cf || State->Flags.Zf;
break;
}
/* JS / JNS */
case 4:
{
Jump = State->Flags.Sf;
break;
}
/* JP / JNP */
case 5:
{
Jump = State->Flags.Pf;
break;
}
/* JL / JNL */
case 6:
{
Jump = State->Flags.Sf != State->Flags.Of;
break;
}
/* JLE / JNLE */
case 7:
{
Jump = (State->Flags.Sf != State->Flags.Of) || State->Flags.Zf;
break;
}
}
if ((Opcode & 0xF0) & 1)
{
/* Invert the result */
Jump = !Jump;
}
if (Jump)
{
/* Move the instruction pointer */
State->InstPtr.Long += Offset;
}
/* Return success */
return TRUE;
}

8
lib/soft386/opcodes.h
View file

@ -79,4 +79,12 @@ Soft386OpcodeExchangeEax
UCHAR Opcode
);
BOOLEAN
FASTCALL
Soft386OpcodeShortConditionalJmp
(
PSOFT386_STATE State,
UCHAR Opcode
);
#endif // _OPCODES_H_